(!!!) (Best Pair) 420A Western Electric NOS 1979 (1.6/1.9ma and 1.6/1.9ma)

1 pair) 420A Western Electric NOS 1979 1-2% matched

1 tube) 1.6/1.9ma Gm=1500/1600

1 tube) 1.6/1.9ma Gm=1400/1500

Matched on Amplitrex

Vplate=180V

Vgrid=-.1V

Good Ma = 1.5-2ma

Good Gm = 1400-1500